package org.springframework.util;
 
import java.beans.Introspector;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
 
/**
 * Miscellaneous class utility methods. Mainly for internal use within the
 * framework; consider
 * <a href="http://commons.apache.org/lang/" target="_blank">Apache Commons Lang</a>
 * for a more comprehensive suite of class utilities.
 *
 * @author Juergen Hoeller
 * @author Keith Donald
 * @author Rob Harrop
 * @author Sam Brannen
 * @since 1.1
 * @see TypeUtils
 * @see ReflectionUtils
 */
@SuppressWarnings("unchecked")
public abstract class ClassUtils {
 
        /** Suffix for array class names: "[]" */
        public static final String ARRAY_SUFFIX = "[]";
 
        /** Prefix for internal array class names: "[" */
        private static final String INTERNAL_ARRAY_PREFIX = "[";
 
        /** Prefix for internal non-primitive array class names: "[L" */
        private static final String NON_PRIMITIVE_ARRAY_PREFIX = "[L";
 
        /** The package separator character '.' */
        private static final char PACKAGE_SEPARATOR = '.';
 
        /** The inner class separator character '$' */
        private static final char INNER_CLASS_SEPARATOR = '$';
 
        /** The CGLIB class separator character "$$" */
        public static final String CGLIB_CLASS_SEPARATOR = "$$";
 
        /** The ".class" file suffix */
        public static final String CLASS_FILE_SUFFIX = ".class";
 
 
        /**
         * Map with primitive wrapper type as key and corresponding primitive
         * type as value, for example: Integer.class -> int.class.
         */
        private static final Map<Class<?>, Class<?>> primitiveWrapperTypeMap = new HashMap<Class<?>, Class<?>>(8);
 
        /**
         * Map with primitive type as key and corresponding wrapper
         * type as value, for example: int.class -> Integer.class.
         */
        private static final Map<Class<?>, Class<?>> primitiveTypeToWrapperMap = new HashMap<Class<?>, Class<?>>(8);
 
        /**
         * Map with primitive type name as key and corresponding primitive
         * type as value, for example: "int" -> "int.class".
         */
        private static final Map<String, Class<?>> primitiveTypeNameMap = new HashMap<String, Class<?>>(32);
 
        /**
         * Map with common "java.lang" class name as key and corresponding Class as value.
         * Primarily for efficient deserialization of remote invocations.
         */
        private static final Map<String, Class<?>> commonClassCache = new HashMap<String, Class<?>>(32);
 
 
        static {
                primitiveWrapperTypeMap.put(Boolean.class, boolean.class);
                primitiveWrapperTypeMap.put(Byte.class, byte.class);
                primitiveWrapperTypeMap.put(Character.class, char.class);
                primitiveWrapperTypeMap.put(Double.class, double.class);
                primitiveWrapperTypeMap.put(Float.class, float.class);
                primitiveWrapperTypeMap.put(Integer.class, int.class);
                primitiveWrapperTypeMap.put(Long.class, long.class);
                primitiveWrapperTypeMap.put(Short.class, short.class);
 
                for (Map.Entry<Class<?>, Class<?>> entry : primitiveWrapperTypeMap.entrySet()) {
                        primitiveTypeToWrapperMap.put(entry.getValue(), entry.getKey());
                        registerCommonClasses(entry.getKey());
                }
 
                Set<Class<?>> primitiveTypes = new HashSet<Class<?>>(32);
                primitiveTypes.addAll(primitiveWrapperTypeMap.values());
                primitiveTypes.addAll(Arrays.asList(
                                boolean[].class, byte[].class, char[].class, double[].class,
                                float[].class, int[].class, long[].class, short[].class));
                primitiveTypes.add(void.class);
                for (Class<?> primitiveType : primitiveTypes) {
                        primitiveTypeNameMap.put(primitiveType.getName(), primitiveType);
                }
 
                registerCommonClasses(Boolean[].class, Byte[].class, Character[].class, Double[].class,
                                Float[].class, Integer[].class, Long[].class, Short[].class);
                registerCommonClasses(Number.class, Number[].class, String.class, String[].class,
                                Object.class, Object[].class, Class.class, Class[].class);
                registerCommonClasses(Throwable.class, Exception.class, RuntimeException.class,
                                Error.class, StackTraceElement.class, StackTraceElement[].class);
        }
 
 
        /**
         * Register the given common classes with the ClassUtils cache.
         */
        private static void registerCommonClasses(Class<?>... commonClasses) {
                for (Class<?> clazz : commonClasses) {
                        commonClassCache.put(clazz.getName(), clazz);
                }
        }
 
        /**
         * Return the default ClassLoader to use: typically the thread context
         * ClassLoader, if available; the ClassLoader that loaded the ClassUtils
         * class will be used as fallback.
         * <p>Call this method if you intend to use the thread context ClassLoader
         * in a scenario where you absolutely need a non-null ClassLoader reference:
         * for example, for class path resource loading (but not necessarily for
         * <code>Class.forName</code>, which accepts a <code>null</code> ClassLoader
         * reference as well).
         * @return the default ClassLoader (never <code>null</code>)
         * @see java.lang.Thread#getContextClassLoader()
         */
        public static ClassLoader getDefaultClassLoader() {
                ClassLoader cl = null;
                try {
                        cl = Thread.currentThread().getContextClassLoader();
                }
                catch (Throwable ex) {
                        // Cannot access thread context ClassLoader - falling back to system class loader...
                }
                if (cl == null) {
                        // No thread context class loader -> use class loader of this class.
                        cl = ClassUtils.class.getClassLoader();
                }
                return cl;
        }
 
        /**
         * Override the thread context ClassLoader with the environment's bean ClassLoader
         * if necessary, i.e. if the bean ClassLoader is not equivalent to the thread
         * context ClassLoader already.
         * @param classLoaderToUse the actual ClassLoader to use for the thread context
         * @return the original thread context ClassLoader, or <code>null</code> if not overridden
         */
        public static ClassLoader overrideThreadContextClassLoader(ClassLoader classLoaderToUse) {
                Thread currentThread = Thread.currentThread();
                ClassLoader threadContextClassLoader = currentThread.getContextClassLoader();
                if (classLoaderToUse != null && !classLoaderToUse.equals(threadContextClassLoader)) {
                        currentThread.setContextClassLoader(classLoaderToUse);
                        return threadContextClassLoader;
                }
                else {
                        return null;
                }
        }
 
        /**
         * Replacement for <code>Class.forName()</code> that also returns Class instances
         * for primitives (like "int") and array class names (like "String[]").
         * <p>Always uses the default class loader: that is, preferably the thread context
         * class loader, or the ClassLoader that loaded the ClassUtils class as fallback.
         * @param name the name of the Class
         * @return Class instance for the supplied name
         * @throws ClassNotFoundException if the class was not found
         * @throws LinkageError if the class file could not be loaded
         * @see Class#forName(String, boolean, ClassLoader)
         * @see #getDefaultClassLoader()
         * @deprecated as of Spring 3.0, in favor of specifying a ClassLoader explicitly:
         * see {@link #forName(String, ClassLoader)}
         */
        @Deprecated
        public static Class<?> forName(String name) throws ClassNotFoundException, LinkageError {
                return forName(name, getDefaultClassLoader());
        }
 
        /**
         * Replacement for <code>Class.forName()</code> that also returns Class instances
         * for primitives (e.g."int") and array class names (e.g. "String[]").
         * Furthermore, it is also capable of resolving inner class names in Java source
         * style (e.g. "java.lang.Thread.State" instead of "java.lang.Thread$State").
         * @param name the name of the Class
         * @param classLoader the class loader to use
         * (may be <code>null</code>, which indicates the default class loader)
         * @return Class instance for the supplied name
         * @throws ClassNotFoundException if the class was not found
         * @throws LinkageError if the class file could not be loaded
         * @see Class#forName(String, boolean, ClassLoader)
         */
        public static Class<?> forName(String name, ClassLoader classLoader) throws ClassNotFoundException, LinkageError {
                Assert.notNull(name, "Name must not be null");
 
                Class<?> clazz = resolvePrimitiveClassName(name);
                if (clazz == null) {
                        clazz = commonClassCache.get(name);
                }
                if (clazz != null) {
                        return clazz;
                }
 
                // "java.lang.String[]" style arrays
                if (name.endsWith(ARRAY_SUFFIX)) {
                        String elementClassName = name.substring(0, name.length() - ARRAY_SUFFIX.length());
                        Class<?> elementClass = forName(elementClassName, classLoader);
                        return Array.newInstance(elementClass, 0).getClass();
                }
 
                // "[Ljava.lang.String;" style arrays
                if (name.startsWith(NON_PRIMITIVE_ARRAY_PREFIX) && name.endsWith(";")) {
                        String elementName = name.substring(NON_PRIMITIVE_ARRAY_PREFIX.length(), name.length() - 1);
                        Class<?> elementClass = forName(elementName, classLoader);
                        return Array.newInstance(elementClass, 0).getClass();
                }
 
                // "[[I" or "[[Ljava.lang.String;" style arrays
                if (name.startsWith(INTERNAL_ARRAY_PREFIX)) {
                        String elementName = name.substring(INTERNAL_ARRAY_PREFIX.length());
                        Class<?> elementClass = forName(elementName, classLoader);
                        return Array.newInstance(elementClass, 0).getClass();
                }
 
                ClassLoader classLoaderToUse = classLoader;
                if (classLoaderToUse == null) {
                        classLoaderToUse = getDefaultClassLoader();
                }
                try {
                        return classLoaderToUse.loadClass(name);
                }
                catch (ClassNotFoundException ex) {
                        int lastDotIndex = name.lastIndexOf('.');
                        if (lastDotIndex != -1) {
                                String innerClassName = name.substring(0, lastDotIndex) + '$' + name.substring(lastDotIndex + 1);
                                try {
                                        return classLoaderToUse.loadClass(innerClassName);
                                }
                                catch (ClassNotFoundException ex2) {
                                        // swallow - let original exception get through
                                }
                        }
                        throw ex;
                }
        }
 
        /**
         * Resolve the given class name into a Class instance. Supports
         * primitives (like "int") and array class names (like "String[]").
         * <p>This is effectively equivalent to the <code>forName</code>
         * method with the same arguments, with the only difference being
         * the exceptions thrown in case of class loading failure.
         * @param className the name of the Class
         * @param classLoader the class loader to use
         * (may be <code>null</code>, which indicates the default class loader)
         * @return Class instance for the supplied name
         * @throws IllegalArgumentException if the class name was not resolvable
         * (that is, the class could not be found or the class file could not be loaded)
         * @see #forName(String, ClassLoader)
         */
        public static Class<?> resolveClassName(String className, ClassLoader classLoader) throws IllegalArgumentException {
                try {
                        return forName(className, classLoader);
                }
                catch (ClassNotFoundException ex) {
                        throw new IllegalArgumentException("Cannot find class [" + className + "]", ex);
                }
                catch (LinkageError ex) {
                        throw new IllegalArgumentException(
                                        "Error loading class [" + className + "]: problem with class file or dependent class.", ex);
                }
        }
 
        /**
         * Resolve the given class name as primitive class, if appropriate,
         * according to the JVM's naming rules for primitive classes.
         * <p>Also supports the JVM's internal class names for primitive arrays.
         * Does <i>not</i> support the "[]" suffix notation for primitive arrays;
         * this is only supported by {@link #forName(String, ClassLoader)}.
         * @param name the name of the potentially primitive class
         * @return the primitive class, or <code>null</code> if the name does not denote
         * a primitive class or primitive array class
         */
        public static Class<?> resolvePrimitiveClassName(String name) {
                Class<?> result = null;
                // Most class names will be quite long, considering that they
                // SHOULD sit in a package, so a length check is worthwhile.
                if (name != null && name.length() <= 8) {
                        // Could be a primitive - likely.
                        result = primitiveTypeNameMap.get(name);
                }
                return result;
        }
 
        /**
         * Determine whether the {@link Class} identified by the supplied name is present
         * and can be loaded. Will return <code>false</code> if either the class or
         * one of its dependencies is not present or cannot be loaded.
         * @param className the name of the class to check
         * @return whether the specified class is present
         * @deprecated as of Spring 2.5, in favor of {@link #isPresent(String, ClassLoader)}
         */
        @Deprecated
        public static boolean isPresent(String className) {
                return isPresent(className, getDefaultClassLoader());
        }
 
        /**
         * Determine whether the {@link Class} identified by the supplied name is present
         * and can be loaded. Will return <code>false</code> if either the class or
         * one of its dependencies is not present or cannot be loaded.
         * @param className the name of the class to check
         * @param classLoader the class loader to use
         * (may be <code>null</code>, which indicates the default class loader)
         * @return whether the specified class is present
         */
        public static boolean isPresent(String className, ClassLoader classLoader) {
                try {
                        forName(className, classLoader);
                        return true;
                }
                catch (Throwable ex) {
                        // Class or one of its dependencies is not present...
                        return false;
                }
        }
 
        /**
         * Return the user-defined class for the given instance: usually simply
         * the class of the given instance, but the original class in case of a
         * CGLIB-generated subclass.
         * @param instance the instance to check
         * @return the user-defined class
         */
        public static Class<?> getUserClass(Object instance) {
                Assert.notNull(instance, "Instance must not be null");
                return getUserClass(instance.getClass());
        }
 
        /**
         * Return the user-defined class for the given class: usually simply the given
         * class, but the original class in case of a CGLIB-generated subclass.
         * @param clazz the class to check
         * @return the user-defined class
         */
        public static Class<?> getUserClass(Class<?> clazz) {
                if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
                        Class<?> superClass = clazz.getSuperclass();
                        if (superClass != null && !Object.class.equals(superClass)) {
                                return superClass;
                        }
                }
                return clazz;
        }
 
        /**
         * Check whether the given class is cache-safe in the given context,
         * i.e. whether it is loaded by the given ClassLoader or a parent of it.
         * @param clazz the class to analyze
         * @param classLoader the ClassLoader to potentially cache metadata in
         */
        public static boolean isCacheSafe(Class<?> clazz, ClassLoader classLoader) {
                Assert.notNull(clazz, "Class must not be null");
                ClassLoader target = clazz.getClassLoader();
                if (target == null) {
                        return false;
                }
                ClassLoader cur = classLoader;
                if (cur == target) {
                        return true;
                }
                while (cur != null) {
                        cur = cur.getParent();
                        if (cur == target) {
                                return true;
                        }
                }
                return false;
        }
 
 
        /**
         * Get the class name without the qualified package name.
         * @param className the className to get the short name for
         * @return the class name of the class without the package name
         * @throws IllegalArgumentException if the className is empty
         */
        public static String getShortName(String className) {
                Assert.hasLength(className, "Class name must not be empty");
                int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
                int nameEndIndex = className.indexOf(CGLIB_CLASS_SEPARATOR);
                if (nameEndIndex == -1) {
                        nameEndIndex = className.length();
                }
                String shortName = className.substring(lastDotIndex + 1, nameEndIndex);
                shortName = shortName.replace(INNER_CLASS_SEPARATOR, PACKAGE_SEPARATOR);
                return shortName;
        }
 
        /**
         * Get the class name without the qualified package name.
         * @param clazz the class to get the short name for
         * @return the class name of the class without the package name
         */
        public static String getShortName(Class<?> clazz) {
                return getShortName(getQualifiedName(clazz));
        }
 
        /**
         * Return the short string name of a Java class in uncapitalized JavaBeans
         * property format. Strips the outer class name in case of an inner class.
         * @param clazz the class
         * @return the short name rendered in a standard JavaBeans property format
         * @see java.beans.Introspector#decapitalize(String)
         */
        public static String getShortNameAsProperty(Class<?> clazz) {
                String shortName = ClassUtils.getShortName(clazz);
                int dotIndex = shortName.lastIndexOf('.');
                shortName = (dotIndex != -1 ? shortName.substring(dotIndex + 1) : shortName);
                return Introspector.decapitalize(shortName);
        }
 
        /**
         * Determine the name of the class file, relative to the containing
         * package: e.g. "String.class"
         * @param clazz the class
         * @return the file name of the ".class" file
         */
        public static String getClassFileName(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                String className = clazz.getName();
                int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
                return className.substring(lastDotIndex + 1) + CLASS_FILE_SUFFIX;
        }
 
        /**
         * Determine the name of the package of the given class:
         * e.g. "java.lang" for the <code>java.lang.String</code> class.
         * @param clazz the class
         * @return the package name, or the empty String if the class
         * is defined in the default package
         */
        public static String getPackageName(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                String className = clazz.getName();
                int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
                return (lastDotIndex != -1 ? className.substring(0, lastDotIndex) : "");
        }
 
        /**
         * Return the qualified name of the given class: usually simply
         * the class name, but component type class name + "[]" for arrays.
         * @param clazz the class
         * @return the qualified name of the class
         */
        public static String getQualifiedName(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                if (clazz.isArray()) {
                        return getQualifiedNameForArray(clazz);
                }
                else {
                        return clazz.getName();
                }
        }
 
        /**
         * Build a nice qualified name for an array:
         * component type class name + "[]".
         * @param clazz the array class
         * @return a qualified name for the array class
         */
        private static String getQualifiedNameForArray(Class<?> clazz) {
                StringBuilder result = new StringBuilder();
                while (clazz.isArray()) {
                        clazz = clazz.getComponentType();
                        result.append(ClassUtils.ARRAY_SUFFIX);
                }
                result.insert(0, clazz.getName());
                return result.toString();
        }
 
        /**
         * Return the qualified name of the given method, consisting of
         * fully qualified interface/class name + "." + method name.
         * @param method the method
         * @return the qualified name of the method
         */
        public static String getQualifiedMethodName(Method method) {
                Assert.notNull(method, "Method must not be null");
                return method.getDeclaringClass().getName() + "." + method.getName();
        }
 
        /**
         * Return a descriptive name for the given object's type: usually simply
         * the class name, but component type class name + "[]" for arrays,
         * and an appended list of implemented interfaces for JDK proxies.
         * @param value the value to introspect
         * @return the qualified name of the class
         */
        public static String getDescriptiveType(Object value) {
                if (value == null) {
                        return null;
                }
                Class<?> clazz = value.getClass();
                if (Proxy.isProxyClass(clazz)) {
                        StringBuilder result = new StringBuilder(clazz.getName());
                        result.append(" implementing ");
                        Class<?>[] ifcs = clazz.getInterfaces();
                        for (int i = 0; i < ifcs.length; i++) {
                                result.append(ifcs[i].getName());
                                if (i < ifcs.length - 1) {
                                        result.append(',');
                                }
                        }
                        return result.toString();
                }
                else if (clazz.isArray()) {
                        return getQualifiedNameForArray(clazz);
                }
                else {
                        return clazz.getName();
                }
        }
 
        /**
         * Check whether the given class matches the user-specified type name.
         * @param clazz the class to check
         * @param typeName the type name to match
         */
        public static boolean matchesTypeName(Class<?> clazz, String typeName) {
                return (typeName != null &&
                                (typeName.equals(clazz.getName()) || typeName.equals(clazz.getSimpleName()) ||
                                (clazz.isArray() && typeName.equals(getQualifiedNameForArray(clazz)))));
        }
 
 
        /**
         * Determine whether the given class has a public constructor with the given signature.
         * <p>Essentially translates <code>NoSuchMethodException</code> to "false".
         * @param clazz the clazz to analyze
         * @param paramTypes the parameter types of the method
         * @return whether the class has a corresponding constructor
         * @see java.lang.Class#getMethod
         */
        public static boolean hasConstructor(Class<?> clazz, Class<?>... paramTypes) {
                return (getConstructorIfAvailable(clazz, paramTypes) != null);
        }
 
        /**
         * Determine whether the given class has a public constructor with the given signature,
         * and return it if available (else return <code>null</code>).
         * <p>Essentially translates <code>NoSuchMethodException</code> to <code>null</code>.
         * @param clazz the clazz to analyze
         * @param paramTypes the parameter types of the method
         * @return the constructor, or <code>null</code> if not found
         * @see java.lang.Class#getConstructor
         */
        public static <T> Constructor<T> getConstructorIfAvailable(Class<T> clazz, Class<?>... paramTypes) {
                Assert.notNull(clazz, "Class must not be null");
                try {
                        return clazz.getConstructor(paramTypes);
                }
                catch (NoSuchMethodException ex) {
                        return null;
                }
        }
 
        /**
         * Determine whether the given class has a method with the given signature.
         * <p>Essentially translates <code>NoSuchMethodException</code> to "false".
         * @param clazz the clazz to analyze
         * @param methodName the name of the method
         * @param paramTypes the parameter types of the method
         * @return whether the class has a corresponding method
         * @see java.lang.Class#getMethod
         */
        public static boolean hasMethod(Class<?> clazz, String methodName, Class<?>... paramTypes) {
                return (getMethodIfAvailable(clazz, methodName, paramTypes) != null);
        }
 
        /**
         * Determine whether the given class has a method with the given signature,
         * and return it if available (else throws an <code>IllegalStateException</code>).
         * <p>Essentially translates <code>NoSuchMethodException</code> to <code>IllegalStateException</code>.
         * @param clazz the clazz to analyze
         * @param methodName the name of the method
         * @param paramTypes the parameter types of the method
         * @return the method (never <code>null</code>)
         * @throws IllegalStateException if the method has not been found
         * @see java.lang.Class#getMethod
         */
        public static Method getMethod(Class<?> clazz, String methodName, Class<?>... paramTypes) {
                Assert.notNull(clazz, "Class must not be null");
                Assert.notNull(methodName, "Method name must not be null");
                try {
                        return clazz.getMethod(methodName, paramTypes);
                }
                catch (NoSuchMethodException ex) {
                        throw new IllegalStateException("Expected method not found: " + ex);
                }
        }
 
        /**
         * Determine whether the given class has a method with the given signature,
         * and return it if available (else return <code>null</code>).
         * <p>Essentially translates <code>NoSuchMethodException</code> to <code>null</code>.
         * @param clazz the clazz to analyze
         * @param methodName the name of the method
         * @param paramTypes the parameter types of the method
         * @return the method, or <code>null</code> if not found
         * @see java.lang.Class#getMethod
         */
        public static Method getMethodIfAvailable(Class<?> clazz, String methodName, Class<?>... paramTypes) {
                Assert.notNull(clazz, "Class must not be null");
                Assert.notNull(methodName, "Method name must not be null");
                try {
                        return clazz.getMethod(methodName, paramTypes);
                }
                catch (NoSuchMethodException ex) {
                        return null;
                }
        }
 
        /**
         * Return the number of methods with a given name (with any argument types),
         * for the given class and/or its superclasses. Includes non-public methods.
         * @param clazz the clazz to check
         * @param methodName the name of the method
         * @return the number of methods with the given name
         */
        public static int getMethodCountForName(Class<?> clazz, String methodName) {
                Assert.notNull(clazz, "Class must not be null");
                Assert.notNull(methodName, "Method name must not be null");
                int count = 0;
                Method[] declaredMethods = clazz.getDeclaredMethods();
                for (Method method : declaredMethods) {
                        if (methodName.equals(method.getName())) {
                                count++;
                        }
                }
                Class<?>[] ifcs = clazz.getInterfaces();
                for (Class<?> ifc : ifcs) {
                        count += getMethodCountForName(ifc, methodName);
                }
                if (clazz.getSuperclass() != null) {
                        count += getMethodCountForName(clazz.getSuperclass(), methodName);
                }
                return count;
        }
 
        /**
         * Does the given class or one of its superclasses at least have one or more
         * methods with the supplied name (with any argument types)?
         * Includes non-public methods.
         * @param clazz the clazz to check
         * @param methodName the name of the method
         * @return whether there is at least one method with the given name
         */
        public static boolean hasAtLeastOneMethodWithName(Class<?> clazz, String methodName) {
                Assert.notNull(clazz, "Class must not be null");
                Assert.notNull(methodName, "Method name must not be null");
                Method[] declaredMethods = clazz.getDeclaredMethods();
                for (Method method : declaredMethods) {
                        if (method.getName().equals(methodName)) {
                                return true;
                        }
                }
                Class<?>[] ifcs = clazz.getInterfaces();
                for (Class<?> ifc : ifcs) {
                        if (hasAtLeastOneMethodWithName(ifc, methodName)) {
                                return true;
                        }
                }
                return (clazz.getSuperclass() != null && hasAtLeastOneMethodWithName(clazz.getSuperclass(), methodName));
        }
 
        /**
         * Given a method, which may come from an interface, and a target class used
         * in the current reflective invocation, find the corresponding target method
         * if there is one. E.g. the method may be <code>IFoo.bar()</code> and the
         * target class may be <code>DefaultFoo</code>. In this case, the method may be
         * <code>DefaultFoo.bar()</code>. This enables attributes on that method to be found.
         * <p><b>NOTE:</b> In contrast to {@link org.springframework.aop.support.AopUtils#getMostSpecificMethod},
         * this method does <i>not</i> resolve Java 5 bridge methods automatically.
         * Call {@link org.springframework.core.BridgeMethodResolver#findBridgedMethod}
         * if bridge method resolution is desirable (e.g. for obtaining metadata from
         * the original method definition).
         * @param method the method to be invoked, which may come from an interface
         * @param targetClass the target class for the current invocation.
         * May be <code>null</code> or may not even implement the method.
         * @return the specific target method, or the original method if the
         * <code>targetClass</code> doesn't implement it or is <code>null</code>
         */
        public static Method getMostSpecificMethod(Method method, Class<?> targetClass) {
                Method specificMethod = null;
                if (method != null && isOverridable(method, targetClass) &&
                                targetClass != null && !targetClass.equals(method.getDeclaringClass())) {
                        specificMethod = ReflectionUtils.findMethod(targetClass, method.getName(), method.getParameterTypes());
                }
                return (specificMethod != null ? specificMethod : method);
        }
 
        /**
         * Determine whether the given method is overridable in the given target class.
         * @param method the method to check
         * @param targetClass the target class to check against
         */
        private static boolean isOverridable(Method method, Class targetClass) {
                if (Modifier.isPrivate(method.getModifiers())) {
                        return false;
                }
                if (Modifier.isPublic(method.getModifiers()) || Modifier.isProtected(method.getModifiers())) {
                        return true;
                }
                return getPackageName(method.getDeclaringClass()).equals(getPackageName(targetClass));
        }
 
        /**
         * Return a public static method of a class.
         * @param methodName the static method name
         * @param clazz the class which defines the method
         * @param args the parameter types to the method
         * @return the static method, or <code>null</code> if no static method was found
         * @throws IllegalArgumentException if the method name is blank or the clazz is null
         */
        public static Method getStaticMethod(Class<?> clazz, String methodName, Class<?>... args) {
                Assert.notNull(clazz, "Class must not be null");
                Assert.notNull(methodName, "Method name must not be null");
                try {
                        Method method = clazz.getMethod(methodName, args);
                        return Modifier.isStatic(method.getModifiers()) ? method : null;
                }
                catch (NoSuchMethodException ex) {
                        return null;
                }
        }
 
 
        /**
         * Check if the given class represents a primitive wrapper,
         * i.e. Boolean, Byte, Character, Short, Integer, Long, Float, or Double.
         * @param clazz the class to check
         * @return whether the given class is a primitive wrapper class
         */
        public static boolean isPrimitiveWrapper(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                return primitiveWrapperTypeMap.containsKey(clazz);
        }
 
        /**
         * Check if the given class represents a primitive (i.e. boolean, byte,
         * char, short, int, long, float, or double) or a primitive wrapper
         * (i.e. Boolean, Byte, Character, Short, Integer, Long, Float, or Double).
         * @param clazz the class to check
         * @return whether the given class is a primitive or primitive wrapper class
         */
        public static boolean isPrimitiveOrWrapper(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                return (clazz.isPrimitive() || isPrimitiveWrapper(clazz));
        }
 
        /**
         * Check if the given class represents an array of primitives,
         * i.e. boolean, byte, char, short, int, long, float, or double.
         * @param clazz the class to check
         * @return whether the given class is a primitive array class
         */
        public static boolean isPrimitiveArray(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                return (clazz.isArray() && clazz.getComponentType().isPrimitive());
        }
 
        /**
         * Check if the given class represents an array of primitive wrappers,
         * i.e. Boolean, Byte, Character, Short, Integer, Long, Float, or Double.
         * @param clazz the class to check
         * @return whether the given class is a primitive wrapper array class
         */
        public static boolean isPrimitiveWrapperArray(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                return (clazz.isArray() && isPrimitiveWrapper(clazz.getComponentType()));
        }
 
        /**
         * Resolve the given class if it is a primitive class,
         * returning the corresponding primitive wrapper type instead.
         * @param clazz the class to check
         * @return the original class, or a primitive wrapper for the original primitive type
         */
        public static Class<?> resolvePrimitiveIfNecessary(Class<?> clazz) {
                Assert.notNull(clazz, "Class must not be null");
                return (clazz.isPrimitive() && clazz != void.class? primitiveTypeToWrapperMap.get(clazz) : clazz);
        }
 
        /**
         * Check if the right-hand side type may be assigned to the left-hand side
         * type, assuming setting by reflection. Considers primitive wrapper
         * classes as assignable to the corresponding primitive types.
         * @param lhsType the target type
         * @param rhsType the value type that should be assigned to the target type
         * @return if the target type is assignable from the value type
         * @see TypeUtils#isAssignable
         */
        public static boolean isAssignable(Class<?> lhsType, Class<?> rhsType) {
                Assert.notNull(lhsType, "Left-hand side type must not be null");
                Assert.notNull(rhsType, "Right-hand side type must not be null");
                if (lhsType.isAssignableFrom(rhsType)) {
                        return true;
                }
                if (lhsType.isPrimitive()) {
                        Class resolvedPrimitive = primitiveWrapperTypeMap.get(rhsType);
                        if (resolvedPrimitive != null && lhsType.equals(resolvedPrimitive)) {
                                return true;
                        }
                }
                else {
                        Class resolvedWrapper = primitiveTypeToWrapperMap.get(rhsType);
                        if (resolvedWrapper != null && lhsType.isAssignableFrom(resolvedWrapper)) {
                                return true;
                        }
                }
                return false;
        }
 
        /**
         * Determine if the given type is assignable from the given value,
         * assuming setting by reflection. Considers primitive wrapper classes
         * as assignable to the corresponding primitive types.
         * @param type the target type
         * @param value the value that should be assigned to the type
         * @return if the type is assignable from the value
         */
        public static boolean isAssignableValue(Class<?> type, Object value) {
                Assert.notNull(type, "Type must not be null");
                return (value != null ? isAssignable(type, value.getClass()) : !type.isPrimitive());
        }
 
 
        /**
         * Convert a "/"-based resource path to a "."-based fully qualified class name.
         * @param resourcePath the resource path pointing to a class
         * @return the corresponding fully qualified class name
         */
        public static String convertResourcePathToClassName(String resourcePath) {
                Assert.notNull(resourcePath, "Resource path must not be null");
                return resourcePath.replace('/', '.');
        }
 
        /**
         * Convert a "."-based fully qualified class name to a "/"-based resource path.
         * @param className the fully qualified class name
         * @return the corresponding resource path, pointing to the class
         */
        public static String convertClassNameToResourcePath(String className) {
                Assert.notNull(className, "Class name must not be null");
                return className.replace('.', '/');
        }
 
        /**
         * Return a path suitable for use with <code>ClassLoader.getResource</code>
         * (also suitable for use with <code>Class.getResource</code> by prepending a
         * slash ('/') to the return value). Built by taking the package of the specified
         * class file, converting all dots ('.') to slashes ('/'), adding a trailing slash
         * if necessary, and concatenating the specified resource name to this.
         * <br/>As such, this function may be used to build a path suitable for
         * loading a resource file that is in the same package as a class file,
         * although {@link org.springframework.core.io.ClassPathResource} is usually
         * even more convenient.
         * @param clazz the Class whose package will be used as the base
         * @param resourceName the resource name to append. A leading slash is optional.
         * @return the built-up resource path
         * @see java.lang.ClassLoader#getResource
         * @see java.lang.Class#getResource
         */
        public static String addResourcePathToPackagePath(Class<?> clazz, String resourceName) {
                Assert.notNull(resourceName, "Resource name must not be null");
                if (!resourceName.startsWith("/")) {
                        return classPackageAsResourcePath(clazz) + "/" + resourceName;
                }
                return classPackageAsResourcePath(clazz) + resourceName;
        }
 
        /**
         * Given an input class object, return a string which consists of the
         * class's package name as a pathname, i.e., all dots ('.') are replaced by
         * slashes ('/'). Neither a leading nor trailing slash is added. The result
         * could be concatenated with a slash and the name of a resource and fed
         * directly to <code>ClassLoader.getResource()</code>. For it to be fed to
         * <code>Class.getResource</code> instead, a leading slash would also have
         * to be prepended to the returned value.
         * @param clazz the input class. A <code>null</code> value or the default
         * (empty) package will result in an empty string ("") being returned.
         * @return a path which represents the package name
         * @see ClassLoader#getResource
         * @see Class#getResource
         */
        public static String classPackageAsResourcePath(Class<?> clazz) {
                if (clazz == null) {
                        return "";
                }
                String className = clazz.getName();
                int packageEndIndex = className.lastIndexOf('.');
                if (packageEndIndex == -1) {
                        return "";
                }
                String packageName = className.substring(0, packageEndIndex);
                return packageName.replace('.', '/');
        }
 
        /**
         * Build a String that consists of the names of the classes/interfaces
         * in the given array.
         * <p>Basically like <code>AbstractCollection.toString()</code>, but stripping
         * the "class "/"interface " prefix before every class name.
         * @param classes a Collection of Class objects (may be <code>null</code>)
         * @return a String of form "[com.foo.Bar, com.foo.Baz]"
         * @see java.util.AbstractCollection#toString()
         */
        public static String classNamesToString(Class... classes) {
                return classNamesToString(Arrays.asList(classes));
        }
 
        /**
         * Build a String that consists of the names of the classes/interfaces
         * in the given collection.
         * <p>Basically like <code>AbstractCollection.toString()</code>, but stripping
         * the "class "/"interface " prefix before every class name.
         * @param classes a Collection of Class objects (may be <code>null</code>)
         * @return a String of form "[com.foo.Bar, com.foo.Baz]"
         * @see java.util.AbstractCollection#toString()
         */
        public static String classNamesToString(Collection<Class> classes) {
                if (CollectionUtils.isEmpty(classes)) {
                        return "[]";
                }
                StringBuilder sb = new StringBuilder("[");
                for (Iterator<Class> it = classes.iterator(); it.hasNext(); ) {
                        Class clazz = it.next();
                        sb.append(clazz.getName());
                        if (it.hasNext()) {
                                sb.append(", ");
                        }
                }
                sb.append("]");
                return sb.toString();
        }
 
        /**
         * Copy the given Collection into a Class array.
         * The Collection must contain Class elements only.
         * @param collection the Collection to copy
         * @return the Class array (<code>null</code> if the passed-in
         * Collection was <code>null</code>)
         */
        public static Class<?>[] toClassArray(Collection<Class<?>> collection) {
                if (collection == null) {
                        return null;
                }
                return collection.toArray(new Class<?>[collection.size()]);
        }
 
        /**
         * Return all interfaces that the given instance implements as array,
         * including ones implemented by superclasses.
         * @param instance the instance to analyze for interfaces
         * @return all interfaces that the given instance implements as array
         */
        public static Class[] getAllInterfaces(Object instance) {
                Assert.notNull(instance, "Instance must not be null");
                return getAllInterfacesForClass(instance.getClass());
        }
 
        /**
         * Return all interfaces that the given class implements as array,
         * including ones implemented by superclasses.
         * <p>If the class itself is an interface, it gets returned as sole interface.
         * @param clazz the class to analyze for interfaces
         * @return all interfaces that the given object implements as array
         */
        public static Class<?>[] getAllInterfacesForClass(Class<?> clazz) {
                return getAllInterfacesForClass(clazz, null);
        }
 
        /**
         * Return all interfaces that the given class implements as array,
         * including ones implemented by superclasses.
         * <p>If the class itself is an interface, it gets returned as sole interface.
         * @param clazz the class to analyze for interfaces
         * @param classLoader the ClassLoader that the interfaces need to be visible in
         * (may be <code>null</code> when accepting all declared interfaces)
         * @return all interfaces that the given object implements as array
         */
        public static Class<?>[] getAllInterfacesForClass(Class<?> clazz, ClassLoader classLoader) {
                Set<Class> ifcs = getAllInterfacesForClassAsSet(clazz, classLoader);
                return ifcs.toArray(new Class[ifcs.size()]);
        }
 
        /**
         * Return all interfaces that the given instance implements as Set,
         * including ones implemented by superclasses.
         * @param instance the instance to analyze for interfaces
         * @return all interfaces that the given instance implements as Set
         */
        public static Set<Class> getAllInterfacesAsSet(Object instance) {
                Assert.notNull(instance, "Instance must not be null");
                return getAllInterfacesForClassAsSet(instance.getClass());
        }
 
        /**
         * Return all interfaces that the given class implements as Set,
         * including ones implemented by superclasses.
         * <p>If the class itself is an interface, it gets returned as sole interface.
         * @param clazz the class to analyze for interfaces
         * @return all interfaces that the given object implements as Set
         */
        public static Set<Class> getAllInterfacesForClassAsSet(Class clazz) {
                return getAllInterfacesForClassAsSet(clazz, null);
        }
 
        /**
         * Return all interfaces that the given class implements as Set,
         * including ones implemented by superclasses.
         * <p>If the class itself is an interface, it gets returned as sole interface.
         * @param clazz the class to analyze for interfaces
         * @param classLoader the ClassLoader that the interfaces need to be visible in
         * (may be <code>null</code> when accepting all declared interfaces)
         * @return all interfaces that the given object implements as Set
         */
        public static Set<Class> getAllInterfacesForClassAsSet(Class clazz, ClassLoader classLoader) {
                Assert.notNull(clazz, "Class must not be null");
                if (clazz.isInterface() && isVisible(clazz, classLoader)) {
                        return Collections.singleton(clazz);
                }
                Set<Class> interfaces = new LinkedHashSet<Class>();
                while (clazz != null) {
                        Class<?>[] ifcs = clazz.getInterfaces();
                        for (Class<?> ifc : ifcs) {
                                interfaces.addAll(getAllInterfacesForClassAsSet(ifc, classLoader));
                        }
                        clazz = clazz.getSuperclass();
                }
                return interfaces;
        }
 
        /**
         * Create a composite interface Class for the given interfaces,
         * implementing the given interfaces in one single Class.
         * <p>This implementation builds a JDK proxy class for the given interfaces.
         * @param interfaces the interfaces to merge
         * @param classLoader the ClassLoader to create the composite Class in
         * @return the merged interface as Class
         * @see java.lang.reflect.Proxy#getProxyClass
         */
        public static Class<?> createCompositeInterface(Class<?>[] interfaces, ClassLoader classLoader) {
                Assert.notEmpty(interfaces, "Interfaces must not be empty");
                Assert.notNull(classLoader, "ClassLoader must not be null");
                return Proxy.getProxyClass(classLoader, interfaces);
        }
 
        /**
         * Check whether the given class is visible in the given ClassLoader.
         * @param clazz the class to check (typically an interface)
         * @param classLoader the ClassLoader to check against (may be <code>null</code>,
         * in which case this method will always return <code>true</code>)
         */
        public static boolean isVisible(Class<?> clazz, ClassLoader classLoader) {
                if (classLoader == null) {
                        return true;
                }
                try {
                        Class<?> actualClass = classLoader.loadClass(clazz.getName());
                        return (clazz == actualClass);
                        // Else: different interface class found...
                }
                catch (ClassNotFoundException ex) {
                        // No interface class found...
                        return false;
                }
        }
 
        /**
         * Check whether the given object is a CGLIB proxy.
         * @param object the object to check
         * @see org.springframework.aop.support.AopUtils#isCglibProxy(Object)
         */
        public static boolean isCglibProxy(Object object) {
                return ClassUtils.isCglibProxyClass(object.getClass());
        }
 
        /**
         * Check whether the specified class is a CGLIB-generated class.
         * @param clazz the class to check
         */
        public static boolean isCglibProxyClass(Class<?> clazz) {
                return (clazz != null && isCglibProxyClassName(clazz.getName()));
        }
 
        /**
         * Check whether the specified class name is a CGLIB-generated class.
         * @param className the class name to check
         */
        public static boolean isCglibProxyClassName(String className) {
                return (className != null && className.contains(CGLIB_CLASS_SEPARATOR));
        }
 
 
}